CN112040393A

CN112040393A - TOF ranging scheduling method

Info

Publication number: CN112040393A
Application number: CN202010766964.2A
Authority: CN
Inventors: 张会军; 罗超; 黄令; 高阳; 杨伟航
Original assignee: Chengdu Sixiangzhi New Technology Co ltd
Current assignee: Chengdu Sixiangzhi New Technology Co ltd
Priority date: 2020-08-03
Filing date: 2020-08-03
Publication date: 2020-12-04
Anticipated expiration: 2040-08-03
Also published as: CN112040393B

Abstract

The application discloses a TOF ranging scheduling method, which improves the capacity of a channel and simultaneously increases the anti-interference capacity of a ranging system, and has a simpler system architecture and lower power consumption of a tag end. The method comprises the following steps: initiating a first time of flight (TOF) ranging request of a label and recording initiation time; judging whether the base station normally replies the first TOF ranging request; determining that the base station replies normally, calculating the initiating time for initiating the second TOF ranging request according to the ranging period of the tag and the initiating time of the first TOF ranging request, and enabling the tag to sleep; and judging whether the base station is continuously and repeatedly abnormally replied or not, determining that the base station is not continuously and repeatedly abnormally replied, calculating the initiation time of initiating the next TOF ranging request according to the ranging period of the tag and the initiation time of the last TOF ranging request, and enabling the tag to sleep.

Description

TOF ranging scheduling method

Technical Field

The invention belongs to the technical field of high-precision positioning, and relates to a TOF ranging scheduling method.

Background

In the field of high-precision positioning, TDOA (Time difference of arrival) and TOF (Time of Flight) are two common positioning methods.

For the TOF positioning mode, a wireless TOF quick positioning method is provided in the related art, and compared with the traditional TOF positioning method, the positioning method shortens the time of a working process and improves the system capacity. Fig. 1 shows a schematic diagram of a tag and base station ranging process. The TOF-based ranging technology is widely applied, and most of the applications based on TOF have the following common points: almost the same TOF period, radio interference, comes almost from between the devices. Higher capacity, lower power consumption, and lower cost are almost all desired for such applications.

There are many common conventional TOF volume boosting methods: for example, time slot scheduled TOF, random TOF and persistent random TOF. The first method has a channel utilization rate close to 100%, but has the problem of complex system, especially the cross-cell time slot scheduling needs to be performed, the complexity is exponentially increased, and the time slot scheduling generally has no anti-interference capability; the second method performs random TOF in a TOF period, which is simple to implement, but the channel utilization rate does not exceed 18.4%; the last method has a higher TOF success rate but the system capacity is reduced due to retransmissions.

Disclosure of Invention

The invention aims to provide a TOF ranging scheduling method, which is used for at least solving the problems in the background technology, improving the channel capacity and the anti-interference capability of a ranging system, and has simpler system architecture and lower power consumption of a tag end.

An embodiment of the present application discloses a TOF ranging scheduling method, including:

initiating a first time of flight (TOF) ranging request of a label and recording initiation time;

judging whether the base station normally replies the first TOF ranging request;

determining that the base station replies normally, calculating the initiating time for initiating the second TOF ranging request according to the ranging period of the tag and the initiating time of the first TOF ranging request, and enabling the tag to sleep;

and judging whether the base station is continuously and repeatedly abnormally replied or not, determining that the base station is not continuously and repeatedly abnormally replied, calculating the initiation time of initiating the next TOF ranging request according to the ranging period of the tag and the initiation time of the last TOF ranging request, and enabling the tag to sleep.

In a preferred embodiment, before the steps of initiating a first TOF ranging request of the tag and recording an initiation time, the method further includes:

carrying out channel monitoring;

judging whether the channel is idle or not;

and if the channel is determined to be idle, initiating a first time of flight (TOF) ranging request of the tag and recording the initiating time.

In a preferred embodiment, if the channel is not idle, the channel monitoring is performed again.

In a preferred embodiment, if the base station does not reply normally, the channel monitoring is performed again.

In a preferred embodiment, if the base station does not normally reply for a plurality of times, the channel monitoring is performed again.

receiving channel data within a period of time, wherein the period of time is less than or equal to the duration of a ranging period;

judging whether the receiving time length of the channel data in the period of time is 0 or not;

if the time length is 0, a first time TOF ranging request of a time length initiating label is randomly waited and the initiating time is recorded, if the time length is not 0, the gap time of the received data is determined, and the first time TOF ranging request of the gap time initiating label is randomly selected to request to record the initiating time.

In a preferred embodiment, if the base station does not reply normally, the channel data is received again within the period of time.

In a preferred embodiment, if the base station does not normally reply for a plurality of times, the base station receives the channel data again in the period of time.

In a preferred embodiment, the ranging periods of all the tags are substantially the same.

The present application also discloses a computer-readable storage medium having stored therein computer-executable instructions which, when executed by a processor, implement the steps in the method as described hereinbefore.

Compared with the prior art, the method has the following beneficial effects:

1) the initial initiation of the ranging request by the tag is random, and once the tag establishes connection with the base station, the tag is equivalent to acquiring a time slot by itself and performing scheduling allocation. The tag obtains the time slot with the base station, only needs to be awakened at a specific moment and interacted with the base station, and does not need to search and monitor the network again, so that the power consumption of the tag is reduced.

2) Each label carries out TOF ranging according to the method, and ranging time slots among the labels are naturally distinguished because each label carries out ranging at the moment based on the base station, so that the problem of interference is avoided, the channel utilization rate is improved, the mutual interference among the labels is reduced, and the capacity of resisting external interference is improved.

3) Compared with a time slot scheduling scheme, the capacity is improved, meanwhile, mutual synchronization among base stations is not needed, the problem of cross-cell is not needed to be considered, and the whole system scheme is simplified.

Drawings

Fig. 1 is a diagram illustrating a ranging procedure between a base station and a tag in the prior art.

Fig. 2 is a flowchart of a TOF ranging scheduling method according to an embodiment of the invention.

Fig. 3 is a flowchart of a TOF ranging scheduling method in a first embodiment according to an embodiment of the present invention.

Fig. 4 is a flowchart of a TOF ranging scheduling method in a second embodiment according to an embodiment of the invention.

Fig. 5 is a diagram illustrating channel utilization according to an embodiment of the invention.

Fig. 6 is a diagram illustrating channel utilization in another embodiment of the present invention.

Detailed Description

In the following description, numerous technical details are set forth in order to provide a better understanding of the present application. However, it will be understood by those skilled in the art that the technical solutions claimed in the present application can be implemented without these technical details and with various changes and modifications based on the following embodiments.

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Part of innovation points of the invention are as follows:

the first TOF ranging request initiated by each label is random, once the label is connected with the base station, the time slot is obtained by itself, and the next TOF ranging request of each label can be determined according to the ranging period and the initiation time, so that the base station can be scheduled and allocated only by waking up a certain label at a specific moment and interacting with the base station without searching and monitoring, and the power consumption of the label is reduced.

Because each label carries out TOF ranging at the moment based on the base station, ranging time slots of all labels are naturally distinguished, so that the problem of interference is avoided, the channel utilization rate is improved, the mutual interference among the labels is reduced, and the external interference resistance is improved.

An embodiment of the present application discloses a TOF ranging scheduling method, and fig. 2 is a flowchart of the ranging method, where the method includes:

step 101, initiating a first time of TOF ranging request of a tag and recording initiation time, wherein the initiation time is the starting time (starting point) of the TOF ranging request.

And step 102, judging whether the base station normally replies the first TOF ranging request.

And 103, determining that the base station returns normally, calculating the initiating time for initiating the second time of TOF ranging request according to the ranging period of the label and the initiating time of the first time of TOF ranging request, and enabling the label to sleep. In one ranging period, there are multiple tags interacting with the base station. In this embodiment, only one base station is used for illustration, and those skilled in the art can understand that there may be a plurality of base stations, and a plurality of tags interact with the plurality of base stations respectively. In a preferred embodiment, the ranging periods of all the tags are substantially the same. It should be noted that, in other embodiments, the specific value of the ranging period may also be determined according to the number of base stations (e.g., one or more base stations) that the tag needs to perform ranging, and may be adjusted according to system requirements.

And step 104, judging whether the base station is continuously and repeatedly abnormally replied, determining that the base station is not continuously and repeatedly abnormally replied, calculating the initiation time of initiating the next TOF ranging request according to the ranging period of the tag and the initiation time of the last TOF ranging request, and enabling the tag to sleep.

In an embodiment, when the tag supports the wireless channel monitoring function, before the step of initiating a first TOF ranging request of the tag and recording the initiation time, the method further includes:

carrying out channel monitoring;

and judging whether the channel is idle, and in the embodiment, if the channel is not idle, monitoring the channel again.

In this embodiment, if the base station does not reply normally, the channel monitoring is performed again.

In this embodiment, if the base station does not normally reply for a plurality of times, the channel monitoring is performed again. In this embodiment, if the base station does not reply for a plurality of times, it indicates that the base station interacts with other tags or is in an abnormal state.

In an embodiment, when the tag does not support the wireless channel monitoring function, before the step of initiating the first TOF ranging request of the tag and recording the initiation time, the method further includes:

if the value is 0, randomly waiting for a first time of TOF ranging request of a time length initiating tag and recording initiating time, wherein the time length can be randomly set, for example, any value smaller than a ranging period, for example, a 1/3 ranging period, a 1/2 ranging period, or initiated immediately; if not, determining the gap time of the received data, and randomly selecting a first time TOF ranging request of a gap time initiating tag to record the initiating time.

In this embodiment, if the base station does not reply normally, the channel data is received again within the period of time.

In this embodiment, if the base station does not reply normally for a plurality of times, the channel data is received again within the period of time.

It should be understood that if the receiving duration of the channel data in a period of time is 0, the data of the channel is not received before the TOF is initiated, an idle time slot is not searched, and a TOF ranging request is directly and randomly initiated; if the receiving time length of the channel data in a period of time is not 0, searching an idle time slot from the received channel data to initiate a TOF ranging request.

In order to explain the technical means of the present invention, the following description will be given with specific examples. It should be understood that these specific examples do not limit the technical solutions of the present invention.

Fig. 3 shows a TOF ranging flow diagram supporting a wireless channel listening function. Firstly, the tag monitors a wireless channel, immediately initiates a TOF ranging request when finding idle, and continues to monitor the channel if the channel is busy. And after the label initiates a TOF ranging request, entering a state of receiving response data of a base station. If the label does not receive normal base station data, the label executes the channel monitoring step again. If the tag receives normal base station data, the tag needs to record the initiating time for initiating the TOF ranging request, and adds a ranging period to the initiating time to serve as the initiating time for sending the TOF ranging request next time by the tag.

After the tag successfully finishes ranging with the base station, the tag calculates the starting point of the next TOF ranging request according to the ranging period and the starting time of the last TOF ranging request, and then the tag sleeps to save power consumption. The time synchronization of the tag and the base station is completed while the ranging of the tag and the base station is carried out, and the interference of the tag caused by poor clock stability is prevented.

And after the label is awakened, initiating the TOF ranging request according to the initiation time of the TOF ranging request obtained by calculating the initiation time of the previous TOF ranging request, and if the label does not receive a reply signal of the base station for a plurality of times, returning the label to the initial state to perform channel monitoring. Otherwise, the label calculates the initiating time of the next TOF ranging request according to the ranging period and the initiating time of the TOF ranging request and enters the sleep mode. The external interference resistance of the distance measurement is improved through the process.

Fig. 4 shows a TOF ranging flow chart that does not support the wireless channel listening function. Fig. 4 is substantially the same as the process of fig. 3, except that: in the ranging process of the tag and the base station, the tag firstly receives channel data for a period of time, calculates the starting point of the idle time according to the receiving time of all the data, and then selects one idle time as the starting point of the TOF ranging request; if the time length of the received data is zero, the label does not select the starting point of the idle time slot any more, and the TOF ranging request is sent directly and randomly.

In the above flow, 1) the tag end has lower energy consumption: in the distance measurement process of the tag and the base station, the tag obtains a time slot with the base station, only needs to wake up at a specific moment to interact with the base station, does not need to search and monitor the network, and reduces the power consumption of the tag; 2) because the tag carries out ranging based on the time of the base station and is naturally distinguished from ranging time slots of other tags, the problem of interference does not exist any more, the utilization rate of a channel is improved, and the mutual interference among the tags is reduced; 3) compared with a time slot scheduling scheme for improving capacity, the method does not need mutual synchronization among base stations and does not need to consider the problem of cross-cell, and the whole system scheme is simplified only by selecting a fixed time starting point.

In general, there are multiple tags in the ranging system, and when all the tags successfully perform the ranging procedure in fig. 3 or fig. 4, the entire channel utilization ratio is between that shown in fig. 5 and that shown in fig. 6, i.e. 50% -100%. Fig. 5 shows a total of n +1 tags in a ranging period, and as shown in fig. 5, when the interval between the start points of any two adjacent tags is just smaller than 2 times the length of TOF time slot, the idle time slot cannot accommodate one tag, and the lowest channel utilization rate is 50%. Fig. 6 shows a total of 2n +2 tags in a ranging period, and as shown in fig. 6, when the interval between the start points of any two adjacent tags is just equal to 1 time of TOF slot length, the highest channel utilization rate at this time is 100%. Wherein, using the ranging procedure shown in fig. 3, this channel utilization is randomly between the highest channel utilization and the lowest channel utilization; using the ranging procedure shown in fig. 4, and when the duration of the received data is just one period, the channel utilization rate is greater than that of the scheme shown in fig. 3, but power consumption is also increased when the tag accesses the channel.

When the tag has determined a TOF start time through the above steps, theoretically, only if the clock stability and accuracy of the tag are high enough, no interference occurs between tags, but due to some factors of the tag, such as: due to cost consideration and environmental influence, the tag cannot use a clock with higher accuracy and stability, and the tag needs to complete time synchronization with the base station when ranging with the base station, so that mutual interference caused by the problem of the tag clock is solved.

Accordingly, other embodiments of the present application may also provide a computer-readable storage medium having stored therein computer-executable instructions that, when executed by a processor, implement the method embodiments of the present application. Computer-readable storage media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

It is noted that, in the present patent application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element. In the present patent application, if it is mentioned that a certain action is executed according to a certain element, it means that the action is executed according to at least the element, and two cases are included: performing the action based only on the element, and performing the action based on the element and other elements. The expression of a plurality of, a plurality of and the like includes 2, 2 and more than 2, more than 2 and more than 2.

In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

Claims

1. A TOF ranging scheduling method, comprising:

2. The TOF ranging scheduling method of claim 1 wherein prior to the steps of initiating a first TOF ranging request by the tag and recording the time of initiation, further comprising:

carrying out channel monitoring;

judging whether the channel is idle or not;

3. The TOF ranging scheduling method of claim 2 wherein if the channel is not idle, then re-performing channel listening.

4. The TOF ranging scheduling method of claim 2 wherein if the base station does not reply normally, channel listening is resumed.

5. The TOF ranging scheduling method of claim 2 wherein if the base station does not normally reply for a plurality of consecutive times, channel listening is resumed.

6. The TOF ranging scheduling method of claim 1 wherein prior to the steps of initiating a first TOF ranging request by the tag and recording the time of initiation, further comprising:

7. The TOF ranging scheduling method of claim 6 wherein if the base station does not reply normally, then re-receiving channel data within the period of time.

8. The TOF ranging scheduling method of claim 6 wherein if the base station does not reply normally a plurality of times in succession, then re-receiving channel data within the period of time.

9. The TOF ranging scheduling method of claim 1 wherein the ranging periods of all tags are substantially the same.

10. A computer-readable storage medium having stored thereon computer-executable instructions which, when executed by a processor, implement the steps of the method of any one of claims 1 to 9.